The present invention relates in general to overbending a folded member and pertains, more particularly to an overbending device for overbending a flap or folded sheet prior to applying a gum or other adhesive, or a sheet of paper or other material to the flap. The overbending device of this invention is an improvement over the conventional plowshare-type overbending devices.
With the conventional envelope making machines one or more flaps are folded to form a complete envelope. Gumming machines, however, typically bend a flap to position the flap for receipt of a gum or latex adhesive. The gum or adhesive is applied in order that the envelope may be sealed with pressure on the gummed portion, either with or without the application of water.
These self-sealing envelopes may require cooperating gum (e.g., latex) deposits applied to both a flap and an enclosure portion of the envelope that form a sealed envelope when pressed together, or pressure sensitive adhesive with a strip of paper material covering the adhesive.
The conventional overbending devices typically satisfy these requirements with a plow share folding member. It is further known to buckle an envelope and flap in order to over bend the flap. These conventional devices are either relatively ineffective, as in the plough share, or relatively complicated devices. The complications typically result from a necessity to manipulate an envelope in order to provide a desired orientation prior to any overbending step.
Accordingly, it is an object of the present invention to provide an improved overbending device that can be adapted for use with existing gumming apparatus. With the overbending device of this invention an additional station may be added to an existing gumming apparatus without substantial alteration or modification of the gumming apparatus.
Another object of the present invention is to provide an improved overbending device that is constructed to operate free of any particular timing requirements. The operation of this invention should only require a modification of the timing of the existing gumming apparatus stations to allow for the additional or altered distance the envelope travels between stations already associated in a timed relationship. A conventional apparatus is expanded, and computing revised timing requirements a simple matter of arithmetic.
A further object of the present invention is to provide an improved overbending device that is adapted to perform with less resistance than conventional overbending devices to thereby reduce the potential for an operational obstruction or other impediment to the desired operation of an associated apparatus, such as a gumming apparatus.